Idiopathic normal pressure hydrocephalus: The key to diagnosis

Abstract

The triad symptoms of idiopathic normal pressure hydrocephalus (iNPH), i.,e., dementia, gait disturbance, and urinary incontinence may appear commonly in the elderly suffering from various brain diseases as well as in those with various non-neurological diseases. Therefore, it is often not easy to differentiate iNPH from other neurological diseases with non-neurological conditions in the elderly. Although ventriculomegaly is a neuroimaging feature of iNPH, differentiation from brain atrophy is not necessarily straight-forward, and in fact many patients with iNPH are often misdiagnosed as having degenerative dementia such as Alzheimer disease. While the prevalence of iNPH is modest, detection of it is particularly important. Disregarding the possibility of iNPH before further diagnostic workup is really unfortunate, as iNPH is possibly curable. On the other hand, as complications associated with shunt surgery and CSF shunting are not negligible, overdiagnosis should be avoided. Since the guidelines for management of iNPH were published, iNPH has been increasingly recognized. In this paper, we focused on the clinical signs and on the neuroimaging and tap test that are all essential for the diagnosis.